Critical issues in connection with human planetary missions: Protection ofand from the environment

Activities associated with human missions to the Moon or to Mars will inter act with the environment in two reciprocal ways: (i) the mission needs to b e protected from the natural environmental elements that can be harmful to human health, the equipment or to their operations; (ii) the specific natur al environment of the Moon or Mars should be protected so that it retains i ts value for scientific and other purposes. The following environmental ele ments need to be considered in order to protect humans and the equipment on the planetary surface: (i) cosmic ionizing radiation, (ii) solar particle events; (iii) solar ultraviolet radiation; (iv) reduced gravity; (v) thin a tmosphere; (vi) extremes in temperatures and their fluctuations; (vii) surf ace dust; (viii) impacts by meteorites and micrometeorites. In order to pro tect the planetary environment, the requirements for planetary protection a s adopted by COSPAR for lander missions need to be revised in view of human presence on the planet. Landers carrying equipment for exobiological inves tigations require special consideration to reduce contamination by terrestr ial microorganisms and organic matter to the greatest feasible extent. Reco rds of human activities on the planet's surface should be maintained in suf ficient detail that future scientific experimenters can determine whether e nvironmental modifications have resulted from explorations. (C) 2001 Elsevi er Science Ltd. All rights reserved.